This update is recommended for all 13-inch and 15-inch MacBook Pro with Retina Display (Late 2013) systems. It includes all updates from OS X Mavericks 10.9.1 plus system specific enhancements to improve the stability and compatibility of your Mac.

Improved support for Gmail in OS X Mail, and fixes for users with custom Gmail settings

Improves the reliability of Smart Mailboxes and search in Mail

Fixes an issue that prevented contact groups from working properly in Mail

Resolves an issue that prevented VoiceOver from speaking sentences that contain emoji